<!DOCTYPE html>
<html lang="cn">
<head>
    <meta charset="UTF-8">
    <title>Document</title>
    <script src="./jquery-1.8.3.min.js"></script>
    
</head>
<body>
    <h1>Jquery</h1>
    <hr>
  
    <script>
        console.log($);

        var $ = 'jingjing';

        console.log($);

        jQuery('h1').css('color', '#f00');

    </script>
    
</body>
</html>